Oscar, Also a specific answer to:
> Suppose that I want to think about a simple 2D problem with a disc rolling down a surface inclined at angle beta with (Coulomb) friction coefficient mu. I want to know when/whether the disc will stick or slip and get the equations of motion for each case. How would I go about doing that using the mechanics module? This is way too simple of a problem to really use the mechanics module for. If I were teaching this I would just use the base sympy features to do the math. The mechanics module is not really geared towards things you find in introductory mechanics in physics and dynamics courses. It is geared toward dynamics of multibodies, 2D and 3D. Most schools teach this at the graduate level or some advanced upper level courses in engineering and physics. I have another package called "resonance" that is aligned more for 2D dynamics and simulation. I do teach the students to derive equations of motion symbolically with sympy and use the resonance interface to do the simulation and analysis. This is here: https://github.com/moorepants/resonance/ Jason moorepants.info +01 530-601-9791 On Tue, May 14, 2019 at 8:59 AM Jason Moore <moorepa...@gmail.com> wrote: > Oscar, > > There are some rolling disc examples here: > https://github.com/pydy/pydy/tree/master/examples Note that the PyDy > project started as an independent thing build on top of SymPy, then the > symbolics were merged into sympy as the mechanic module and the numerics > are now in the standalone PyDy package. > > Also, I teach an entire graduate class using the module that include 20+ > lecture videos and accompanying notebooks: > https://moorepants.github.io/mae223/ > > There are also several scipy/pycon tutorials on the package: > > http://www.moorepants.info/portfolio/pydy.html > > The module may be complicated, but that may just reflect that 3D multibody > rigid body mechanics is complicated. We've worked on some layers on top of > the core code that have been merged or are in open PRs to help provide > simpler interfaces that give a way to "assemble" bodies as you would in > reality (with joints, etc) but it is still not polished for production. I > could imagine a layer that makes it simpler to do 2D mechanics too, among > other things. > > I'll be working on things this summer because I am teaching the > aforementioned course in the fall. Feel free to open issues for discussion > on improvements. > > Jason > moorepants.info > +01 530-601-9791 > > > On Mon, May 13, 2019 at 1:42 PM Oscar Benjamin <oscar.j.benja...@gmail.com> > wrote: > >> Hi all, >> >> I haven't really looked much at SymPy's mechanics module even though >> mechanics is very much one of my interests and something that I like >> to think I know a bit about. Today I finally took a look at it and I >> found the whole API surprisingly complicated. I teach mechanics to >> undergraduate students but I'm not sure if I would know how to teach >> my students to use the mechanics module as it is now... >> >> Firstly I looked through the documentation here: >> https://docs.sympy.org/latest/modules/physics/mechanics/index.html >> Is there any other guide/documentation that explains the general ideas >> more simply with examples? >> >> Suppose that I want to think about a simple 2D problem with a disc >> rolling down a surface inclined at angle beta with (Coulomb) friction >> coefficient mu. I want to know when/whether the disc will stick or >> slip and get the equations of motion for each case. How would I go >> about doing that using the mechanics module? >> >> -- >> Oscar >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sympy+unsubscr...@googlegroups.com. >> To post to this group, send email to sympy@googlegroups.com. >> Visit this group at https://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/CAHVvXxQXtAd_HGwTqaKrpDqQC_mNcyZAFgPrVe8Sq_hPwT6H0w%40mail.gmail.com >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAP7f1AgY%3Dcq3q9DCAYk_0-4qV8rhoVZTTJp7WJku8A%2BX2%3Df_Mg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
